1. local company using database system.

Oracle8i Distributed Database Systems

The local Oracle database server breaks the distributed query into a corresponding number of remote queries, which it then sends to the remote nodes for execution. The remote nodes execute the queries and send the results back to the local node. The local node then performs any necessary post-processing and returns the results to the user or application.

2. foreign company using database system

The Foreign Companies in Bahrain Yearbook 2009 and CD-Rom 2009 is a researched company database of major international companies in Bahrain.

A unique Bahraini companies directory, the Foreign Companies in Bahrain Yearbook database provides hard-to-find information on this growing emerging market. The Bahrain database features670 fully researched, senior executive contacts and top decision makers at 180 multinational companies in Bahrain, across 37 industry sectors. The Bahrain Yearbook also covers detailed international company profiles on parent company head offices worldwide.

Answer the following:

1. Describe the nature of their database system/s.
Using Collocated Inline Views

The most effective way of optimizing distributed queries is to access the remote databases as little as possible and to retrieve only the required data.

2. What are the benefits derived by the company, its personnel and management, clients and other stakeholders.

• Managing the Distribution of an Application's Data

• Controlling Connections Established by Database Links

• Maintaining Referential Integrity in a Distributed System

• Tuning Distributed Queries

• Handling Errors in Remote Procedures

3. Cite the reference in your post

Maintaining Referential Integrity in a Distributed System

If a part of a distributed statement fails, for example, due to an integrity constraint violation, Oracle returns error number ORA-02055. Subsequent statements or procedure calls return error number ORA-02067 until a rollback or rollback to savepoint is issued.

Design your application to check for any returned error messages that indicate that a portion of the distributed update has failed. If you detect a failure, you should roll back the entire transaction before allowing the application to proceed.

Oracle does not permit declarative referential integrity constraints to be defined across nodes of a distributed system. In other words, a declarative referential integrity constraint on one table cannot specify a foreign key that references a primary or unique key of a remote table. Nevertheless, you can maintain parent/child table relationships across nodes using triggers.

If you decide to define referential integrity across the nodes of a distributed database using triggers, be aware that network failures can limit the accessibility of not only the parent table, but also the child table. For example, assume that the child table is in the SALES database and the parent table is in the HQ database. If the network connection between the two databases fails, some DML statements against the child table (those that insert rows into the child table or update a foreign key value in the child table) cannot proceed because the referential integrity triggers must have access to the parent table in the HQ database.

4. Refrain from copying texts from the net

http://www.mcs.csuhayward.edu/support/oracle/doc/8.1.7/server.817/a76960/ds_appde.htm{http://www.bharatbook.com/Market-Research-Reports/Foreign-Companies-in-Bahrain-2009.html}